Method for controlling weeds with amino acid higher alkyl esters

ABSTRACT

A herbicidal composition comprising a herbicidal amount of an active compound selected from the group consisting of acid addition salts of higher alkyl esters of amino acids, acid addition salts of N-lower alkyl substitution products of said esters and quaternary ammonium salts of N-lower alkyl substitution products of said esters, and a diluent or carrier, and a method for controlling weeds using said herbicidal composition.

This invention relates to a herbicidal composition of an amino acidhigher alkyl ester type which has an excellent weed controlling effect,especially a germination inhibitory activity and a herbicidal activity,and which exhibits a markedly reduced toxicity on man, poultry, domesticanimals, fish and other non-mammalian aquatic animals and also a reducedresidual toxicity in soil; and to a method for controlling weeds.

The herbicidal composition of this invention is useful for controllingweeds growing in various loci such as fields, paddies, orchards, forestsand gardens, but can be applied especially preferably to post-emergenceweed control for agriculture and horticulture in fields, paddies andorchards, especially for controlling weeds in paddies.

Active compounds of the carbamate, acid amide, diphenylether,s-triazine, urea and dipyridyl types have previously been used asherbicides against weeds in fields and paddies, but these conventionalherbicides have not been entirely satisfactory in respect of residualtoxicity in soil and toxicity on man, poultry, domestic animals, fishand other non-mammalian aquatic animals. Thus, their use has beenlimited because of the need to control pollution.

The inventors of the present application have been engaged in thedevelopment of herbicides which exhibit an excellent herbicidal effectwithout posing any such pollution problem. As a result, they found thatan active compound selected from the group consisting of acid additionsalts of higher alkyl esters of amino acids, preferably those in whichthe alkyl group contains 8 to 22 carbon atoms, acid addition salts ofN-lower alkyl substitution products of said alkyl esters, preferablythose in which the lower alkyl group contains 1 to 4 carbon atoms, andquaternary ammonium salts of N-lower alkyl substitution products of saidalkyl esters exhibits an excellent germination inhibitory activity and aherbicidal activity on broadleaf weeds in the paddy field such asbarnyard-grass (Echinochloa oryzicola VASING), Monachoria vaginalisPRESL, Eleocharis acicularis ROEM et SHULT, and Cyperus difformis L. andupland weeds such as Digifaria adscendens HENR, or Amaranthus viridis L.without causing such a pollution problem. It has also been found thatthe above active compounds exhibit an outstanding effect within a veryshort period of time, for example, within 2 to 3 days, against broadleafweeds in paddy fields, the effect being not reduced even in a floodedpaddy field, and has no phytotoxicity on rice plants, and further thatthe compound exhibits an excellent herbicidal activity on the aboveupland weeds without phytotoxicity on plants cultivated in upland.

It is therefore an object of this invention to provide a herbicidalcomposition of an amino acid higher alkyl ester type herbicidalcomposition having an excellent herbicidal effect and causing nopollution problem with its markedly reduced toxicity on man, domesticanimals, poultry, fish and other non-mammalian aquatic animals and alsoa markedly reduced residual toxicity in soil; and a method for weedcontrol using this composition.

The active compound in the herbicidal composition of this invention isselected from the group consisting of acid addition salts of higheralkyl esters, preferably C₈₋₂₂ higher alkyl esters, of amino acids, acidaddition salts of N-lower alkyl substitution products, preferably C₁₋₄lower alkyl substitution products, of said esters, and quaternaryammonium salts of N-lower alkyl substitution products of said esters.Preferred active compounds are, for example, those of the followingformulae (1) and (2). ##STR1## wherein R₁ is a member selected from thegroup consisting of a hydrogen atom, alkyl groups containing 1 to 4carbon atoms, ##STR2## and H₂ N.(CH₂)₄ ; R₂ is an alkyl group containing8 to 22 carbon atoms; Y is a hydrogen atom or methyl group; R₃ and R₄are each a member of the group consisting of a hydrogen atom and amethyl group; Z is an inorganic or organic acid group; and n is 0 or aninteger of 1 to 5, and when n is an integer of 1 to 5, both of R₁ and Yare hydrogen atoms; ##STR3## wherein Y and R₂ are the same as definedwith respect to formula (1).

Various amino acids such as α-amino acid, β-amino acid, and ω-amino acidcan be utilized as the amino acid component of the compounds of formula(1) and (2) above. Examples of preferred amino acids are glycine,alanine, β-alanine, valine, norvaline, leucine, isoleucine, norleucine,tyrosine, threonine, 2-aminoisobutyric acid, 6-aminocaproic acid,lysine, and arginine, and N--C₁₋₄ alkyl substitution products, such asN-methyl or N-ethyl substitution products, of these, such as glycinebetaine, N,N'-dimethylvaline, and N,N'-dimethylalanine. The amino acidsmay be optically active ones or racemic modifications.

Examples of the ester portion of the above preferred compounds offormulae (1) and (2) are esters of straight chain or branched alkylscontaining 8 to 22 carbon atoms such as octyl, decyl, lauryl, myristyl,cetyl, stearyl, 2-hexyldecyl and 2-octyldecyl esters. Of these, thedecyl and lauryl esters are preferred.

Both organic acids and inorganic acids can be utilized as the acid groupZ which forms an acid addition salt in the formula (1). Examples ofpreferred acids are hydrochloric acid, acetic acid, p-toluenesulfonicacid, oxalic acid, and pyroglutamic acid.

The solubility of the active component used in this invention differsaccording to the type of the acid addition salt, the number of carbonatoms of the alkyl esters, etc., but generally, it is water-soluble.Where the solubility of the active ingredient is very low, it ispreferred to utilize a suitable dispersing agent.

The active ingredient used in this invention can be used conjointly withother known herbicides or fungicides. The conjoint use of it with aknown herbicide, 3,3'-dimethyl-4-methoxybenzophenone has been found toexhibit a unique synergistic effect. The3,3'-dimethyl-4-methoxybenzophenone has an excellent herbicidal effectwhen applied in the pre-emergence stage, but does not show asatisfactory herbicidal effect when applied in the post-emergence stage.When this 3,3'-dimethyl-4-methoxybenzophenone is used in admixture withthe active ingredient used in the present invention, the mixture showsan excellent synergistic herbicidal effect in post-emergenceapplication. It may be recommended that the active compound (A) of thisinvention and the 3,3'-dimethyl-4-methoxybenzophenone (B) are used in an(A):(B) weight ratio of 2:8 to 8:2, more preferably 4:6 to 6:4.

The herbicidal composition of this invention can be formulated in anydesired formulation such as dust, granule, pellet, wettable powder,emulsifiable concentrate or dispersed liquid using various solid andliquid diluent or carriers known in the art. Examples of solid diluentsor carriers are clay, white carbon, bentonite, kaolin, diatomaceousearth, starch, and gum arabic, with or without a dispersing agent oremulsifier. Examples of liquid diluents or carriers are water, watercontaining a dispersing agent or emulsifier, dioxane, isophorone orethanol. The above-mentioned dispersing agent or emulsifier may, forexample, be soap, sulfuric acid esters of higher alcohols,alkylsulfonate salts, quaternary ammonium salts, polyalkylene oxides,polyoxyalkylene ethers, or alkali metals or calcium salts ofligninsulfonic acid.

The amount of the above diluent or carrier to be used in the compositionof this invention can be suitably selected, and for example, the contentof the active compound (including a mixture of the active compounds) canbe about 1 to about 99% by weight based on the weight of the herbicidalcomposition. The amount of the active compound can be suitably selectedalso according to the type of formulation. For example, the amount maybe about 10 to about 90% by weight in the case of emulsifiableconcentrate, suspension or wettable powder, and it may be frequentlyabout 10 to about 30% by weight when the formulation is granule orpellet.

According to this invention, there can be provided a method forcontrolling weeds, which comprises applying to weeds or the locus whereweeds are growing or will grow a herbicidal amount of an active compoundselected from the group consisting of acid addition salts of higheralkyl esters of amino acids, acid addition salts of N-lower alkylsubstitution products of said esters and quaternary ammonium salts ofN-lower alkyl substitution products of said esters. The active compoundcan be applied as a mixture of it with a known herbicide,3,3'-dimethyl-4-methoxybenzophenone.

The application of the herbicidal composition of this invention ispreferably done in the post-emergence stage. For example, thecomposition is applied to weeds in paddies desirably in the early stageof germination. As will be shown later in the Examples, the herbicidalcomposition of this invention exhibits an excellent herbicidal effectwithout causing phytotoxicity even when applied to the period of growthof weeds after rice plant seedlings have been transplanted in paddies.In order to control upland weeds, a foliar treatment of weeds with theherbicidal composition of this invention gives good results.

The rate of application of the active ingredients can be suitably variedaccording to the time of application, the type of weeds, the type of theactive compound, and the type of formulation. Generally, the rate of theherbicidal composition to be applied is about 50 to about 100 g per are.Often, amounts of about 100 to about 400 g per are are employed in thecase of upland weeds, and about 50 to about 150 g per are in the case ofweeds in paddies. When a mixture of the active compound and3,3'-dimethyl-4-methoxybenzophenone is used, the preferred amount of themixture is about 30 to about 60 g per are.

Examples of the herbicide of this invention are shown below. All partsin the Examples are by weight.

EXAMPLE 1

Glycine lauryl ester DL-pyroglutamate (20 parts), 2 parts of whitecarbon, 2 parts of sodium ligninsulfonate, 4 parts of a polyoxyethylenealkyl ether and 72 parts of clay were mixed and pulverized to form 100parts of a wettable powder.

EXAMPLE 2

DL-valine lauryl ester hydrochloride (10 parts), 15 parts of starch, 72parts of bentonite and 3 parts of a sodium salt of lauryl alcoholsulfate ester were mixed and pulverized to form 100 parts of granules.

EXAMPLE 3

Betaine lauryl ester hydrochloride (50 parts), 10 parts of an emulsifier(SORPOL, a registered tradename for a product of Toho Chemical Co.,Ltd., Japan) and 40 parts of water were mixed to form 100 parts of anemulsifiable concentrate.

The control effect of the herbicide of this invention against weeds inpaddies and upland weeds will be described below.

EXAMPLE 4

Treatment of irrigated soil:

Soil from a rice paddy field was filled in synthetic resin pots eachhaving an inside diameter of 8 cm, and seeds of rice plant (Nihonbarevariety), barnyard grass (Echinochloa oryzicola VASING), Monochoriavaginalis PRESL., and other broad-leaf weeds were sown. Then, the potswere irrigated so that the depth of water became 3 cm. Then, at thestage where the first leaves sprouted (in the case of barnyard grass)and at the stage of growth (the other weeds), these weeds were treatedwith an aqueous solution of the active ingredient in the amountindicated in Table 1 (those not soluble in water were first dissolved indioxane and then in water). Ten days after the treatment, the treatedpots were examined for a herbicidal effect and the state of growth ofthe weeds. The results are shown in Table 1 according to the followingscale of evaluation.

                  Table 1                                                         ______________________________________                                        Rate         Herbicidal Effect                                                       (Active   Echino-   Mona-                                                     ingredi-  chloa     choria Broad-                                                                              Cyperus                               Compound                                                                             ent)      oryzicola vaginalis                                                                            leaf  difformis                             No.    g/a       VASING    PRESL  weed  L.                                    ______________________________________                                         1*    100       3         2      4     4                                     2      100       3         2      4     4                                            50        3         2      4     3                                     3      100       4         2      4     2                                            50        3         2      4     2                                     4      100       4         4      4     4                                            50        4         4      4     4                                            25        3         3      3     3                                     5      100       4         2      4     3                                     6      100       3         1      3     3                                      7*    100       3         2      3     3                                     8      100       4         2      4     3                                     9      100       4         4      4     4                                            50        4         4      4     4                                            25        3         3      3     3                                     10     100       3         1      2     2                                     11     100       2         2      1     2                                     12     100       2         2      2     2                                     13     100       2         2      2     2                                     14     100       2         2      2     2                                     15     100       2         3      3     2                                     16     100       2         2      2     2                                     ______________________________________                                         Note                                                                          1* N,N-dimethyl-DL-valinelauryl ester                                         2 Glycine lauryl ester                                                        3 DL-alaninelauryl ester                                                      4 DL-valinelauryl ester hydrochloride                                         5 DL-leucinelauryl ester                                                      6 Glycinedecyl ester hydrochloride                                            7* DL-tyrosine lauryl ester                                                   8 DL-threoninedecyl ester                                                     9 2-aminoisobutyric acid lauryl ester                                         10 DL-lysine lauryl ester                                                     11 Betaine lauryl ester hydrochloride                                         12 DL-aspartic acid lauryl ester                                              13 DL-glutamic acid lauryl ester                                              14 DL-tyrosine lauryl ester                                                   15 DL-alanine lauryl ester oxalate                                            16 ε-Aminocaproic acid lauryl ester DL-pyroglutamate                  [*insoluble in water (dissolved in water after having been dissolved in       dioxane)                                                                 

Herbicidal effect:

0: none

1: slight

2: ordinary

3: strong

4: the weeds were withered

EXAMPLE 5

Herbicidal effect on various weeds in paddies:

The following plants (unless otherwise specified, they were all in the5-leaf stage) were transplanted in synthetic resin pots each having aninside diameter of 12 cm. The pots were irrigated to a water depth of 4cm. After these plants rooted (7 days later), they were treated with achemical liquid containing a predetermined amount of the activeingredient dissolved therein. The plants were examined 6 days after thetreatment. The standard of evaluation was the same as in Example 4.

                                      Table 2                                     __________________________________________________________________________    (Weeding spectrum)                                                                        Herbicidal effect                                                       Compound                                                                            2   3   4   4   5   9   9                                         Weeds                                                                             g/a                                                                             No.   200 200 200 100 200 200 100                                       __________________________________________________________________________    Lobelia chinensis                                                             LOUR        4   4   4   4   4   4   4                                         Lindernia                                                                     procumbens PHILCOX                                                                        4   4   4   4   4   4   4                                         Vandellia                                                                     angustifolia BENTH                                                                        3   4   4   4   3   4   4                                         Dopatrium                                                                     junceum HAMILT                                                                            3   4   4   4   3   4   4                                         Ludwigia prostrata                                                            ROXB.       4   4   4   4   4   4   4                                         Rotala indica                                                                 KOEHNE      4   4   4   4   4   4   4                                         Elatine triandra                                                              SCHK        4   4   4   4   4   4   4                                         Callitriche                                                                   Verna L.    4   4   4   4   4   4   4                                         Monochoria                                                                    vaginalis PRESL.                                                                          3   4   4   4   3   4   4                                         Aneilema Keisak                                                               HASSK.      2   2   2   2   2   2   2                                         Echinochloa                                                                   Oryzicola                                                                     VASING      4   4   4   4   4   4   4                                         Spirodela poly-                                                               rhiza SCHLEID.                                                                            4   4   4   4   4   4   4                                         Lemna paucicostata                                                            HEGELM      4   4   4   4   4   4   4                                         Potamogeton                                                                   distinctus A. BENN.                                                                       3   3   3   3   3   3   3                                         Cyperus difformis                                                             L           4   4   4   4   4   4   4                                         Eleocharis                                                                    acicularis ROME                                                               et SCHULT   3   3   4   3       4   3                                         __________________________________________________________________________     Note:                                                                         The compound numbers are the same as those described in the footnote to       Table 1.                                                                 

EXAMPLE 6

Herbicidal activity in an overflooded condition:

A chain link was placed in the lower layer of Wagner pots (1/5000 are),and pebbles and sand were successively packed onto it. Soil of a ricepaddy was filled in the pots as an upper layer. A cock was fixed to thedischarge opening at the bottom of the pot so that water at a desiredflow rate could be discharged from the pot. Seeds of barnyard grass(Echinochloa oryzicola VASHING), Monochoria vaginalis PRESL., and otherbroadleaved weeds were sown, and at the same time, rice plant seedlings(Nihonbare variety) were transplanted in the pots. At the beginning ofgrowing of weeds (3 days after the transplantation) and at the stage ofgrowth of the weeds (8 to 10 days after the transplantation), a chemicalliquid containing a predetermined amount of the active ingredientdissolved therein was applied to the weeds. For 3 days after thetreatment, the water was overflooded at a rate of 2 cm/day, andthereafter, the weeds were allowed to grow in an irrigated conditionwith a water depth of 3 cm. On the 24th day after the transplantation,the remaining weeds were pulled up, and their dry weight was measured.The weight was compared with that in a non-treated lot, and the rate ofcontrol was calculated according to the following equation, and theresults are shown in Table 3. ##EQU1##

                  Table 3                                                         ______________________________________                                                    Rate of control (%)                                                                     Echi-                                                                         no-                                                                           chloa             Cy-                                         Treat-          ory-  Mona-       perus Phy-                                  ing             zi-   choria      dif-  to-                             Com-  con-    Flood-  cola  vagi- Broad-                                                                              form- tox-                            pound di-     ed      VAS-  nalis leaf  is    ici-                            No.   tions*  water   ING   PRESL weed  L     ty                              ______________________________________                                        4     +3,     -       90    100   100   60    -                                     100g/a  +       80    100   100   90    -                                     +3,     -       50    90    90    60    -                                     50g/a   +       80    100   100   60    -                                     +3,     -       30    100   80    80    -                                     25g/a   +       90    100   90    60    -                                     +10,    -       20    70    100   30    -                                     100g/a  +       80    100   100   80    -                                     +10,    -       10    70    80    10    -                                     50g/a   +       80    90    90    60    -                                     +3,     -       90    100   100   80    -                                     50g/a                                                                         +10,    +       80    100   100   80    -                                     50g/a                                                                   9     +3,     -       100   100   90    50    -                                     100g/a  +       100   90    100   80    -                                     +3,     -       100   90    90    70    -                                     50g/a   +       100   90    90    30    -                                     +8,     -       100   90    100   90    -                                     100g/a  +       100   90    100   90    -                                     +8,     -       30    80    100   80    -                                     50g/a   +       100   90    100   80    -                               ______________________________________                                         Note:                                                                         The compound numbers were the same as those in Table 1.                       * +3, +8 and +10 respectively mean that the treatment was performed on th     3rd, 8th and 10th day after the transplatation.                          

As demonstrated above, the active compounds in accordance with thisinvention exhibited a high herbicidal effect even when used in a floodedpaddy field on the 3rd to the 10th day after the transplantation, andcaused no phytotoxicity on rice plants.

Some examples of formulation of the mixed active ingredient will beshown below.

EXAMPLE 7

Dl-valine lauryl ester hydrochloride; 25 parts

3,3'-dimethyl-4-methoxybenzophenone; 25 parts

White carbon; 2 parts

Sodium ligninsulfonate; 2 parts

Polyoxyethylene alkyl ether; 4 parts

Clay; 42 parts

The above ingredients were mixed and pulverized to form 100 parts of awettable powder.

EXAMPLE 8

Dl-valinelauryl ester hydrochloride; 7 parts

3,3'-dimethyl-4-methoxybenzophenone; 7 parts

Bentonite; 76 parts

Calcium ligninsulfonate; 10 parts

The above ingredients were mixed uniformly, and granulated to form 100parts of granules.

Examples will further be given in order to illustrate the herbicidaleffect of the mixed active ingredient against weeds in paddies.

                  Table 4                                                         ______________________________________                                                Amount                                                                        of                                                                            Chemi-                                                                              Rate of residual weeds (%)                                              cal   Barnyard grass                                                            (act.   Be-    1 -               Cy-                                          ive     fore   leaf  1.5 -       perus                                        ingre-  the    to    to          dif-                                         dient   one-   1.5 - 2 -   Broad-                                                                              form-                              Chemi-    (g/     leaf   leaf  leaf  leaved                                                                              is                                 cals      are)    stage  stage stage grass L                                  ______________________________________                                              No. 1   3.2     90   100   100   100   100                                            10      70   75    80    60    85                                             18      40   40    60    30    60                                             32      10   20    30    10    40                                             56      0    10    30    5     40                                     No. 2   3.2     80   90    100   70    95                                             10      40   70    85    50    80                                             18      10   40    45    20    50                                             32      0    10    10    10    30                                             56      0    0     5     0     30                                     No. 3   3.2     70   90    100   60    70                                             10      40   60    70    35    50                               Single        18      10   40    40    20    50                               com-          32      0    20    20    2     20                               pound         56      0    0     0     0     20                                     No. 4   3.2     80   95    100   75    70                                             10      50   60    65    30    50                                             18      20   20    30    10    40                                             32      0    5     10    5     10                                             56      0    0     0     0     10                                     DMB     3.2     10   70    70    20    3                                              10      0    40    40    2     1                                              18      0    30    30    4     0                                              32      0    20    30    0     0                                              56      0    10    30    0     0                                      No. 1   18      0    10    15    0     0                                      DMB     18                                                              Mix-  No. 2   18      0    8     9     0     0                                tures DMB     18                                                                    No. 3   18      0    8     15    0     0                                      DMB     10                                                                    No. 3   18      0    7     9     0     0                                      DMB     18                                                                    No. 3   18      0    0     7     0     0                                      DMB     18                                                                    No. 4   18                                                                    DMB     18      0    0     8     0     0                                ______________________________________                                    

the following Example shows the control effect of the compounds offormula (2) against upland weeds.

EXAMPLE 9

Soil from fields was filled in synthetic resin pots each having aninside diameter of 8 cm, and seeds of barnyard grass, Amaranthus viridisL. and Digitaria adscendens HENR. were sown. At the 2- to 3-leaf stage,an aqueous solution of each of the effective components in a prescribedamount was sprayed on the leaves of the weeds in an amount of 10 ml. perpot using a spray gun. The state of growth was observed on the 7th dayfrom the treatment, and the herbicidal effect was shown on the samescale as used in Example 4. The results are shown in Table 5 below.

                  Table 5                                                         ______________________________________                                                     Herbicidal effect                                                                                      Digitaria                               Compound                                                                              Concentra- Barnyard Amaranthus                                                                             adscendens                               No.     tion (ppm) grass    viridis L.                                                                             HENR.                                    ______________________________________                                        1       1000       3        3        3                                                2000       3        4        3                                        2       1000       3        3        3                                                2000       4        4        4                                        3       1000       3        3        3                                                2000       3        4        3                                        ______________________________________                                         Note:                                                                         No. 1: Betaine decylester                                                     No. 2: Betaine lauryl ester                                                   No. 3: Betaine myristyl ester hydrochloride                              

What we claim is:
 1. A method for controlling Lobelia chinensis LOUR,Lindernia procumbens PHILCOX, Vandellia Angustifolia BENTH, Dopatriumjunceum HAMILT, Ludwigia prostrata ROXB., Rotala indica KOEHNE, Elatinetriandra SCHK, Callitriche Verna L., Monochoria vaginalis PRESL.,Aneilema Keisak HASSK., Echinochloa Oryzicola VASING, Spirodelapolyrhiza SCHLEID., Lemna paucicostata HEGELM, Potamogeton distinctus A.BENN., Cyperus difformis L, Eleocharis acicularis ROME et SCHULT,Amaranthus viridis L., or Digifaria adscendens HENR. weeds, whichcomprises applying to said weeds, or the locus where said weeds aregrowing or will grow, a herbicidal amount of an active compound selectedfrom the group consisting of acid addition products of higher alkylesters of amino acids, acid addition salts of N-lower alkyl substitutionproducts of said esters and quaternary ammonium salts of N-lower alkylsubstitution products of said esters wherein said active compound isselected from compounds of formula (1) ##STR4## wherein R₁ is a memberselected from the group consisting of a hydrogen atom, alkyl containing1 to 4 carbon atoms, ##STR5## R₂ is alkyl containing 8 to 22 carbonatoms, Y is a hydrogen atom or methyl, each of R₃ and R₄ is a memberselected from the group consisting of a hydrogen atom and lower alkyl of1 to 4 carbon atoms, Z is an inorganic or organic acid group selectedfrom the group consisting of hydrochloric acid, acetic acid, p-toluenesulfonic acid, oxalic acid and pyroglutamic acid, n is 0 or an integerof 1 to 5 and, when an integer of 1 to 5, both R₁ and Y are hydrogenatoms, and compounds of formula (2) ##STR6## wherein Y and R₂ are thesame as defined above.
 2. The method of claim 1 wherein the rate of saidactive compound to be applied is 50 to 100 g per are.
 3. The method ofclaim 1 wherein said active compound is selected from compounds offormula (1).
 4. The method of claim 1 wherein said active compound isapplied in the post-emergence stage.
 5. The method of claim 1 whereinsaid active compound is selected from the group consistingofN,n-dimethyl-DL-valinelauryl ester oxalate, Glycine lauryl esterDL-pyroglutamate, Dl-alaninelauryl ester hydrochloride, Dl-valinelaurylester hydrochloride, Dl-leucinelauryl ester hydrochloride, Glycinedecylester hydrochloride, Dl-threoninedecyl ester hydrochloride,2-aminoisobutyric acid lauryl ester hydrochloride, Betaine lauryl esterhydrochloride, Dl-alanine lauryl ester oxalate, ε-aminocaproic acidlauryl ester DL-pyroglutamate, Betaine decyl ester hydrochloride, andBetaine myristyl ester hydrochloride.
 6. The method of claim 1 whereineach of R₃ and R₄ is a member selected from the group consisting of ahydrogen atom and methyl.